578 CALIFORNIA ACADEMY OF SCIENCES. 



gether near the tip or but one spine so situated that 

 the rostrum may appear either trifid or bifid. The car- 

 apax is not crested in front. There is a supra -orbital 

 spine and two spines on the anterior margin of the car- 

 apax the upper one of which is situated just below a short 

 suborbital tooth. The antennules are provided with two 

 long flagella which usually do not differ markedly in 

 length; the outer flagellum presents a tolerably well 

 marked division into a basal portion and a more slender 

 and somewhat longer distal part. The first joint of the 

 antennular peduncle is transversely hollowed out and 

 furnished with an external spine which usually extends a 

 little beyond the tip. The antennal scale reaches about 

 to the tip of the rostrum and the flagella often exceed the 

 length of the body. The mandibles are devoid of a palp 

 and are divided (but not deeply so) into a molar process 

 and a broad, thin, dentate cutting edge. 



The maxillipeds do not reach the tips of the antennal 

 scales but generally exceed the tips of the peduncles; 

 the exopod may reach beyond the tip of the penultimate 

 joint and alwa3'S exceeds the third one ; the last joint is 

 longer than the preceding one and is furnished with a 

 row of spines on the distal third of the inner margin. 



All of the pereopods, except the last pair, are furnished 

 with exopods. The first pair is short, the carpus short, 

 distally widened; hand oblong, not very much broader 

 than thick; at the proximal end is a rounded process 

 which fits into a concavity in the distal end of the carpus; 

 fingers nearly as long as the palm, excavated within, the 

 tips rounded and furnished with a dense tuft of setfE. 

 Second pereopods longer than the first but shorter than 

 the third; carpus not annulated, hand slender, strongly 

 incurved; fingers with setas at the tip. The three fol- 

 lowing pairs of pereopods are subequal ; the tarsi are not 



